1. Field of the Invention
The present invention relates to a through silicon via structure, and more particularly to the double through silicon via structure having an improved circuit structure to prevent the defects of short circuit and broken circuit.
2. Description of the Related Art
Through-Silicon Via (TSV) packaging technology is an interconnect technology of the 3D package that follows the Moore's Law, and the TSV stacks a plurality of chips like a sandwich to form an electrically interconnected three-dimensional stack package, wherein the TSV promotes the 2D chip layout technology to the 3D stack technology and already starts its operation in production lines already. The TSV three-dimensional stack technology includes the thinning and boring of wafers, and the filling of via with a conductive material, and the connection of wafers in order to combine the wafers as a whole. The TSV three-dimensional interconnect technology has a shorter interconnect path, a lower resistance, a lower inductance and a more efficient signal and power transmission than those of the wire bonding as well as the advantage of having no particular limitation on the quantity of stacked dies, and thus the TSV technology has been adopted in the areas of CMOS sensor, and memory and will be applied in the areas of baseband, radio frequency and process very soon. The TSV technology can efficiently enhance both integrity and performance for the system with a lower cost.
However, a plurality of conventional TSVs is coupled to each other through the same node and the driving circuit and coupled to the receiving circuit through the same node, so that if one of the TSVs has a defect of short circuit, the other TSVs will be shortly circuited as well. In other words, signals passing through the good TSV may be attenuated or restricted to 0. In addition, the TSV may have a defect of open circuit because of damages of the conductor, a void between the TSV and a bonding pad or a dislocation occurred during the bonding process.
In view of the aforementioned problems, it is a main subject for the present invention to provide a double TSV structure to improve the tolerance of the double through silicon via towards the defects of short circuit and open circuit.